Long before the Romans, Iberian settlers built on the high ground and kept watch from the great limestone rock that now bears the name Penyal d'Ifac. It was the perfect lookout, a sheer mass rising straight from the water and visible for miles in every direction. Inland, the Morro de Toix offered a second vantage, guarding the Mascarat Ravine, the narrow passage that any traveller along this coast had to thread. When Arab rulers took the region, they raised a castle above that ravine. Even after the Crown of Aragon conquered the area, the older order held: scattered settlements, each dependent for its safety on the Castle of Calpe. To live here was to know exactly where you would run when the horizon turned dangerous.

In 1290 the Aragonese admiral Roger of Lauria ordered a village raised near the rock and called it Ifach. It did not last. In 1359, during the War of the Two Peters, Peter IV of Aragon against Peter I of Castile, Ifach was destroyed, and its survivors crowded into the alqueria, from the Arabic al-qarya, the small town. These were humble buildings, one or two floors of plain stone set against the hillside. By 1386 the old district of the Castle of Calpe had been carved into the four towns still on the map today: Benissa, Teulada, Calpe, and Senija.

The sea's oldest threat arrived in 1637. Barbary corsairs out of Algiers fell on the Valencian coast and struck Calpe directly. When they sailed away, they carried 315 people with them into slavery, most of them women and children, taken from homes that had stood, until that morning, in the supposed safety of the shore. The raid left a wound the town answered with stone. Through the mid-eighteenth century Calpe laboured to throw a new fortified wall around itself, because by then its own growth had pushed too many families to live beyond the reach of the old defences. For a coastal town the sea was never only a livelihood; it was also the direction from which disaster reliably came, and Calpe built accordingly.

Peace, when it came, smelled of brine. Through the nineteenth century the fishing industry grew, and a Fisherman's Cooperative rose beside older salting factories. In 1918 the El Saladar salt flats were cleared and the salt pans worked again; today that same lagoon is a sanctuary where migratory birds, flamingos among them, stalk the shallows. The first small hotels appeared near the Queen's Baths and Raco beach, and in 1935 the Ifach Parador opened to summer visitors. Then, in the 1960s, came the great Costa Blanca building boom. For a few years around 1970 the town even doubled as a film set for the Spanish director Jesus Franco.

There is one more line that crosses Calpe, invisible and arbitrary and strangely fitting for a town so long obsessed with knowing its position. The Greenwich meridian, zero degrees longitude, the reference from which the world measures east and west, passes through the municipality on its way south. Wander the old centre and the deeper past is easier to see: a Gothic church, the eighteenth-century watchtower of La Peca, and always, over every rooftop, the pale bulk of the rock that has watched over all of it. Today Calpe is a resort of some twenty-seven thousand people whose economy still rests on the two things it always has, tourism and fishing, the trawlers unloading each afternoon at the port while visitors climb toward the summit. The town even keeps friends abroad, twinned with Oppenheim in Germany and El Puerto de Santa Maria in Andalusia.